Not Applicable.
The invention relates to concrete retaining wall blocks and more particularly to a method and apparatus for handling concrete retaining wall blocks.
Retaining walls have been constructed from precast concrete blocks. The blocks are sometimes cast in a form having four sides and a bottom. The top of the form is open for pouring concrete into the form. Sometimes a heavy wire loop formed, for example, from a bent piece of rebar, is embedded into the block. The wire loop extends from the block to facilitate lifting the block from the form, transporting the block, and stacking the blocks to construct a retaining wall. Alternately, the wire loop may be located in a recess in the block surface so that it does not interfere with stacking the blocks. One common method for moving the blocks is to pass a chain through the wire loop and over a tine on a fork lift. Either the fork lift operator has to get off of the fork lift to attach the chain, or a second worker is needed to attach the chain.
In some cases, retaining wall blocks are cast in a form with the front or face of the block down, so that the wire loop extends from the back of the block. The wire loop is useful for lifting the block from a form in which it was cast. However, a wire loop must be located on the top of and near the center of the block in order to lift the block in a horizontal orientation for stacking when constructing a wall. Sometimes blocks have been formed with a first wire loop extending from the back of the block for lifting the block from the form in which it was cast, and with a second wire loop in a recess in the top surface of the block for use in stacking the block. After the block is lifted from the form, it is turned so that the bottom of the block is down and the chain is moved to the wire loop in the top of the block for lifting the block onto a truck for transportation and for stacking the block to form a retaining wall. This may require a forklift driver to dismount the forklift at least twice in attaching a chain to the two different wire loops, or it may require the use of a second worker for attaching, moving and detaching the chain.
The invention is directed to a method and apparatus for handling large concrete retaining wall blocks and similar heavy cast concrete articles. The blocks may weight, for example, between 500 and 3,000 pounds, or more, depending on their size and configuration. The blocks are cast in a form with a front side or face of the blocks down. The bottom of the form may include a textured insert for imparting a desired texture and pattern on the front surface of the block. The sides of the form define a top, a bottom, a left side and a right side of the cast block. The rear side of the block is formed at an open top of the form. When the block is cast, ends of a heavy wire loop are inserted into the uncured concrete to extend from the rear side of the block near its center. Once a cast block has sufficiently cured to be handled without risk of breaking, the sides of the form are separated from the sides, top and bottom of the block.
According to one aspect of the invention, a spear hook is secured to one tine of a fork lift. The spear hook is angled to a side of the tine so as to not interfere with use of the tine for lifting. The fork lift is manipulated to engage the wire loop extending from the rear side of the block with a hooked end of the spear hook, and the block is lifter clear of the form. The block may then be placed in a temporary storage area or on a truck for transportation. Preferably, the block is set down on its face and the fork lift is manipulated to rotate the block so that its bottom is down. The spear hook is then manipulated to disengage the wire loop.
According to a second aspect of the invention, fork lift grooves are formed in the left and right sides of the cast block to extend substantially parallel to the top and bottom of the block and to extend from the rear side of the block to a location short of the front face of the block. Consequently, when the blocks are stacked to form a retaining wall, the fork lift grooves are not visible. After the block is oriented with its bottom down, the fork lift can approach the block from its rear side, engage the fork lift grooves and lift the block. The fork lift grooves can be used both for lifting the blocks onto and off of a truck for transportation and for stacking the blocks to form a retaining wall. Thus, with the apparatus and method of the invention, a fork lift driver can handle the blocks without the need to get off the fork lift for attaching and detaching a chain to the blocks, and without the need for an additional worker to attach and detach chains.
Accordingly, it is an object of the invention to provide a method and apparatus for handling concrete retaining wall blocks and similar large concrete products.
Other objects and advantages of the invention will become apparent from the following detailed description of the invention and the accompanying drawings.